1. Acenes, Fullerenes and Carbon Nanotubes Glen P. Miller Department of Chemistry and Materials Science Program University of New Hampshire Columbia University September 17, 2008

2. Acenes: Polycyclic aromatic hydrocarbons composed of linearly annelated benzene rings (Clar, E. Polycyclic Hydrocarbons ; Academic Press Inc: London, 1964; Vol. 1, pp 4-5)

3. Acene Applications

5. Acene Degradation: Competing Photo-Oxidation Mechanisms

6. Substituent Effects on Acene Longevity

7. Kinetics of Photo-Oxidation “ Substituent Effects in Pentacenes: Gaining Control Over HOMO-LUMO Gaps and Photo-oxidative Resistances,” submitted to JACS

8. Kinetics of Photo-Oxidation “ Substituent Effects in Pentacenes: Gaining Control Over HOMO-LUMO Gaps and Photo-oxidative Resistances,” submitted to JACS

9. Evidence for Singlet Oxygen Chemistry

10. Lessons Learned: Location, Location, Location

11. Lessons Learned: Steric Resistance is Important “ Substituent Effects in Pentacenes: Gaining Control Over HOMO-LUMO Gaps and Photo-oxidative Resistances,” submitted to JACS

12. Lessons Learned: ED and EW Groups Offer Unique Electronic Effects “ Substituent Effects in Pentacenes: Gaining Control Over HOMO-LUMO Gaps and Photo-oxidative Resistances,” submitted to JACS

13. Steric & Electronic Effects Combined “ Substituent Effects in Pentacenes: Gaining Control Over HOMO-LUMO Gaps and Photo-oxidative Resistances,” submitted to JACS

14. Arylthio and Alkylthio Substituted Pentacenes are the Big Winners

15. Thin-Film Characteristics “ Substituent Effects in Pentacenes: Gaining Control Over HOMO-LUMO Gaps and Photo-oxidative Resistances,” submitted to JACS

16. HOMO & LUMO Energies

17. HOMO & LUMO Energies and Gaps pentacene derivative (t 1/2 ) E 1/2 [O] a (mV) E 1/2 [red] a (mV) E HOMO (eV) E LUMO (eV) E g,EChem (eV) low energy  max (nm) E g,optical (eV) c E HOMO,DFT , E LUMO,DFT (eV) E g,DFT (eV) 1 (1140) 849, 1093 -1099 -5.17 -3.36 1.81 624, 575, 534 1.86 -5.20, -3.03 2.17 2 (750) 755, 936 -1229, -1726 -5.07 -3.26 1.81 617, 570, 529 1.88 -5.08, -2.89 2.19 3 (620) 899 -1227 -5.21 -3.24 1.97 605, 559, 520 1.94 --- --- 4 (520) 789 -1054 -5.11 -3.42 1.69 643, 591, 548 1.81 -5.08, -3.07 2.01 5 (220) 713 -1485 -5.03 -2.99 2.04 605, 558, 520 1.95 --- --- 6 (40) 695 -1478 -5.01 -3.00 2.01 604, 557, 518 1.96 -4.93, -2.71 2.22 7 (13) 638, 1372 -1543 -4.95 -2.93 2.02 618, 569, 529 1.90 --- --- 8 (9.0) 627, 1224 -1430 -4.93 -3.07 1.86 600, 554, 515 1.93 --- --- 9 (8.5) 682 -1396 -5.00 -3.08 1.92 604, 558, 519 1.94 -4.86, -2.63 2.23 10 (7.3) 536, 1171 -1521 -4.86 -2.97 1.89 602, 556, 518 1.92 --- --- 11 (6.6) 464, 1081 -1651 -4.78 -2.84 1.94 583, 539, 501 2.01 --- --- 12 (3.7) 635, 1183 -1407 -4.95 -3.07 1.88 621, 573, 532 1.88 -4.80, -2.59 2.21 Pentacene (7.5) f 582, 537, 501 2.08 -2.67, -4.96 2.29

18. Computing HOMO & LUMO Energies Blue Cells = Electrochemically Derived Values Green Cells = Computationally Predicted Values Yellow Cells = Mean Absolute Deviations (MAD) All Energies Reported in eV DFTtzv = B3LYP/6-311+G** DFTdzv = B3LYP/6-31G* Pent. HOMO (Expt.) LUMO (Expt.) Gap (Expt.) HOMO (DFTtzv) LUMO (DFTtzv) Gap (DFTtzv) HOMO (DFTdzv) LUMO (DFTdzv) Gap (DFTdzv) 1 -5.17 -3.36 1.81 -5.20 -3.03 2.17 -4.78 -2.7 2.08 2 -5.07 -3.26 1.81 -5.08 -2.89 2.19 -4.69 -2.59 2.10 3 -5.11 -3.42 1.69 -5.08 -3.07 2.01 4 -5.01 -3.00 2.01 -4.93 -2.71 2.22 -4.54 -2.39 2.15 5 -5.00 -3.08 1.92 -4.86 -2.63 2.23 -4.49 -2.33 2.16 6 -4.95 -3.07 1.88 -4.80 -2.59 2.21 -4.43 -2.27 2.16 MAD=0.07 MAD=0.38 MAD=0.32 MAD=0.45 MAD=0.70 MAD=0.24

20. HOMO-LUMO Energy Gaps for [n]Acenes: (n = 2-9) B3LYP/6-31G*

21. Comparing Basis-Sets for [n]Acenes: 6-31G* vs. 6-311+G** B3LYP/6-311+G**//B3LYP/6-31G* B3LYP/6-31G* Green = Closed-Shell Solutions Blue = Open-Shell Solutions Ring # [n] HOMO (eV) LUMO (eV) Gap 2 -6.14 -1.41 4.73 3 -5.57 -2.04 3.53 4 -5.20 -2.46 2.74 5 -4.94 -2.76 2.18 6 -4.74 -2.98 1.76 7 -6.72 -5.31 1.41 8 -6.02 -4.62 1.40 9 -6.72 -5.56 1.16 HOMO LUMO Gap -6.09 -1.40 4.69 -5.53 -2.02 3.51 -5.16 -2.44 2.72 -4.90 -2.74 2.16 -4.71 -2.96 1.75 -4.70 -2.98 1.72 -4.67 -3.03 1.64 -4.62 -3.08 1.54

22. Comparing Basis-Sets for [n]Acenes: 6-31G* vs. 6-311+G** B3LYP/6-31G* Green = Closed-Shell Solutions Blue = Open-Shell Solutions B3LYP/6-311+G**//B3LYP/6-31G* Ring # [n] HOMO (eV) LUMO (eV) Gap 2 -6.14 -1.41 4.73 3 -5.57 -2.04 3.53 4 -5.20 -2.46 2.74 5 -4.94 -2.76 2.18 6 -4.74 -2.98 1.76 7 -4.74 -3.00 1.74 8 -4.70 -3.05 1.65 9 -4.66 -3.11 1.55 HOMO LUMO Gap -6.09 -1.40 4.69 -5.53 -2.02 3.51 -5.16 -2.44 2.72 -4.90 -2.74 2.16 -4.71 -2.96 1.75 -4.70 -2.98 1.72 -4.67 -3.03 1.64 -4.62 -3.08 1.54

23. Approaching “Band-Gap Engineering”: Substituent Effects on Pentacene Derivatives 6,13-Disubstituted Pentacenes: Geometries, Energies and Surfaces Computed from B3LYP/6-311+G** R HOMO LUMO GAP -O - 3.72 4.13 0.41 -NH 2 -4.10 -2.45 1.65 -OH -4.89 -2.78 2.11 -H -4.96 -2.67 2.29 -SCH 3 -5.08 -2.89 2.19 -CN -5.70 -3.76 1.94 -CCH -5.05 -3.12 1.93 -CHO -5.50 -3.66 1.84 -S + (CH 3 ) 2 -10.94 -9.20 1.74 Recall: Hexacene Gap = 1.8 Heptacene Gap = 1.7

24. Exploiting Substituent Effects to Prepare Large, Persistent Acenes

25. C 60 – Pentacene Monoadduct J. Mack and G. P. Miller, Fullerene Science & Technology 1997 , 5 , 607 Fullerene-Acene Chemistry

26. G. P. Miller, J. Briggs, J. Mack, P. A. Lord, M. M. Olmstead, A. L. Balch, Organic Letters 2003 , 5 , 4199 Fullerene-Acene Chemistry

27. 85% Isolated 6,13-Diphenylpentacene Fullerene-Acene Chemistry G. P. Miller and J. Mack, Organic Letters 2000 , 2 , 3979

28. G. P. Miller, J. Mack, and J. Briggs, Organic Letters 2000 , 2 , 3983 Fullerene-Fullerene  Stacking

29. Fullerene-Fullerene  Stacking G. P. Miller, J. Briggs, J. Mack, P. A. Lord, M. M. Olmstead, A. L. Balch, Organic Letters 2003 , 5 , 4199

30.  -  Stacking in Graphite: d = 3.35 Å

31. Spacial Dependence of [60]Fullerene-[60]Fullerene  -  Stacking Interactions 1 1.1 G. P. Miller and J. Briggs, Tetrahedron Letters 2004 , 45 , 477

33. Nonacene Cyclodecacene Path Forward: Making Cyclacenes Using Fullerene-Acene Chemistry

34. Path Forward: Making SWNCs Using Cyclacenes

35. SWNCs with Uniform, Tunable Properties: Band-Gap Engineering G. P. Miller, S. Okana, D. Tománek, J. Chem. Phys . 2006 , 124 , 121102

36. Other Nanostructured Carbons

37. Fullerene Nanotubes

38. [60]Fullerene Nanotubes Rauwerdink, K., Liu, J.-F., Kintigh, J. and Miller, G. P., Microscopy Research & Technique , 2007 , 70 , 513-521

39. Functionalized Fullerenes & Fullerene Nanotubes for OPVs

40. Functionalized Fullerenes & Fullerene Nanotubes for OPVs

41. Acknowledgements